The present invention relates to systems and methods for the guided removal of objects in vivo. In particular, the invention is directed to a removal device adapted to traverse compact areas utilizing a navigation mechanism, and more specifically, to capture and/or remove debris through a vacuum tube that is in communication with a suction source.
Kidney stones are a common medical problem that negatively impact millions of individuals worldwide. Kidney stones include one or more solid masses of material that are usually made of crystals and form in parts of the urinary tract including in the ureter, the kidney, and/or the bladder of the individual. Kidney stones range in size from smaller (less than about 1 cm) to very large (more than 4 cm) and may cause significant pain to the individual and damage to the kidney. The overwhelming majority of stones that are treated by surgeons are less than 1 cm.
The recommended treatment for removal of the kidney stones varies according to numerous factors including the size of the kidney stones, the number of kidney stones, and the location of the kidney stones. The most common treatments for kidney stones are shock wave lithotripsy (ultrasound waves used to fracture the stones), ureteroscopy (fracture and removal of the stones using an endoscope that is introduced through the bladder), and percutaneous nephrolithotomy (fracture and removal of the stones using an endoscope that is introduced through a sheath placed through the patient's back into the kidney).
The largest kidney stones are usually removed through percutaneous nephrolithotomy or nephrolithotripsy, or through other similar procedures. In these procedures, a small incision is made through the patient's back adjacent the kidney and a sheath is passed into the kidney to accommodate a larger endoscope used to fracture and remove stones. The stone may be removed directly through the tube or may be broken up into small fragments while still in the patient's body and then removed via a vacuum or other known methods (nephrolithotripsy).
There are numerous drawbacks associated with nephrolithotomy, nephrolithotripsy, and other invasive surgeries requiring an incision in the skin. Namely, such surgical techniques may require significantly more anesthesia administered to the patient, the surgeries are more complicated and pose a higher risk of infection and complications for the patient, and the surgeries require a substantial incision in the patient, which may leave a scar. Additionally, given the invasiveness of the procedure, percutaneous procedures are usually not preferred for smaller kidney stones (e.g., less than 1 cm) depending on the size and location of the stones.
In contrast, traditionally, smaller kidney stones have been treated using other, less invasive techniques including through ureteroscopy. In ureteroscopy, the surgeon typically inserts a ureteroscope into the urethra through the bladder and the ureter to provide the surgeon with a direct visualization of the kidney stone(s) which may reside in the ureter or kidney. The surgeon then removes the kidney stone directly using a basketing device if the kidney stone is small enough to pass through the urinary tract without difficulty, or the surgeon fractures the kidney stone into smaller pieces using a laser or other breaking device. After breaking the kidney stone into smaller pieces, the surgeon removes the laser or breaking device and inserts a basket or other object to capture the kidney stone fragments. Upon retrieving some of the kidney stone fragments, the surgeon removes the basket from the patient and empties the kidney stone fragments therefrom. This process is repeated until clinically significant kidney stones and kidney stone fragments are broken up and removed from the body.
It should be apparent that this process is extremely time consuming, costly, and inefficient because the surgeon is required to insert and remove the scope and basket into and out of the patient many times to completely remove the kidney stones and kidney stone fragments therefrom. Using a basket removal device to capture kidney stones or kidney stone fragments suffers from other drawbacks in that the basket is difficult to position adjacent the kidney stone fragments and maneuver in a manner that effectively retrieves the fragments. The training required for such a procedure is not insignificant and the aforementioned basket removal technique is difficult for even the most skilled surgeons. Additionally, the surgeon is susceptible to hand fatigue due to the extended amount of time required to operate the kidney stone retrieval baskets. Further, the patient is required to be under local anesthesia and/or remain immobile over an extended amount of time. Still further, the basket retrieval devices cause irritation to the urinary tract due to the repeated insertion and removal therefrom.
Other kidney stone removal techniques may utilize suction devices to remove kidney stones and kidney stone fragments from the patient. Such techniques use a flexible tube designed to be disposed within a working channel of a ureteroscope. The flexible tube is designed to have a diameter of between 2 French and 3 French and includes a suction source therethrough. Utilization of this type of device necessarily restricts the size of the passageway available to remove kidney stones and portions thereof from the patient. Indeed, the diameter of the ureteroscope occupies a significant portion of the limited passageway into the patient. Therefore, the size of the flexible tube is bounded by the size of the working channel of the ureteroscope and is defined by a diameter of under about 3 French. The utilization of the working channel of a ureteroscope or other viewing instrument has heretofor been utilized to assist the surgeon in locating the matter to be removed from the patient and to assist in guiding the removal instruments to an appropriate location. The use of these devices is necessarily restricted to removal of debris that is smaller than the size of the tube disposed in the working channel (i.e., under about 3 French). Accordingly, the prior art devices of this type are unable to remove debris greater than about 2 mm and removal of even smaller stones becomes problematic given the narrow lumen size in the prior art devices and their resulting propensity to clog, even with stones of 1 mm or less.
Kidney stone removal techniques may also make use of irrigation systems, devices, and methods to remove stone fragments from the patient. Irrigation is often used during a ureteroscope procedure.
For example, some prior-art devices use irrigation to introduce a liquid, such as water or saline solution, into the kidney. Such irrigation can be used to perform a cleansing that washes very small particles out of the remote interior regions of the kidney. However, any liquid that is introduced must drain from the kidney both during and after the procedure. Therefore, the volume of liquid that can be introduced is necessarily limited, and there is no strong liquid flow to remove fragments that are wetted by the liquid from the kidney. A more effective irrigation procedure is needed to rapidly and reliably remove particles, fragments and debris from the kidney.
A stent may be introduced following removal of stones from a kidney. A retrograde Pyelogram contrast study can be used to both verify that all clinically-relevant fragments have been removed, and to evaluate the extent of injury to the urinary collecting system. In particular, a contrast study provides information on the extent of extravasation of blood and other bodily fluids, which is indicative of the extent of injury. Information gained from a contrast study is useful in making decisions on where to place a stent and how long to leave it in place.
Thus, to further facilitate adoption of new systems, methods, and devices for kidney stone removal, it is desirable to ensure compatibility with stent placement. Placement of a stent after the removal procedure results in improved drainage and accelerated healing. It is not uncommon for edema of the ureter to occur post-procedure, resulting in significant pain. Improving drainage through placement of a stent can reduce the extent of such edema and associated pain. Furthermore, studies show that dilation of the ureter by a stent contributes to more rapid healing. For these reasons, a stent is used in the majority of such procedures worldwide, and in the overwhelming majority of stone removal procedures in the United States. Accordingly, new methods and devices that address the removal of debris greater than about 3 mm and are compatible with stent placement are desirable.